Grating has been used for many years in structural applications such as for areas of pedestrian traffic, catwalks, work platforms, etc. In addition to structural grating applications, many architects find grating attractive for architectural grillework, screens, dividers, etc. Thus, it can be seen that grating is ideal for a wide range of indoor and outdoor applications.
In most applications, grating is used to provide for the maximum passage of heat, light and air. However, the desirability of such maximum passage must be balanced against the necessity of having a strong, rigidly constructed and safe grating assembly for a particular application, especially where failure of the grating could cause serious personal injury and/or property damage.
The closest known prior art includes two types of grating construction which, although satisfactory for many applications, do not perform satisfactorily when used in certain other applications. The first type of prior art grating construction is pressure locked grating which comprises crossbars pressed into bearing bars under hydraulic or mechanical pressure to force the crossbars into slots formed in the bearing bars. Although pressure locked grating performs satisfactorily for many applications and features a level grating surface formed by the crossbars and bearing bars, pressure locked grating generally is not as structurally sound or as economical to manufacture as my improved grating construction.
The second type of prior art grating construction comprises crossbars which are slideably mounted within apertures formed in the bearing bars. The crossbars then are swaged on both sides of each bearing bar to secure the crossbars firmly in the bearing bars to form the grating. Although swage locked grating also performs satisfactorily in many applications and is one of the sturdiest and safest types of grating constructions, it has one main disadvantage. The crossbars of the grating are mounted beneath the top surface of the bearing bars and do not form a level grating surface with the bearing bars. Also, these lowered crossbars are difficult to see in certain applications. Thus, although this type of swage locked grating is, in fact, sturdy and safe, it may not appear so to a person walking on the grate or using the grating due to the manner of engagement of the crossbars with the center of the bearing bars. That is, it appears to a person walking on this type of grating that the bearing bars are the sole means of support. Psychologically, seeing crossbars which form a level grating surface with the bearing bars gives a greater feeling of security to a person using the grating since he or she can actually see that the crossbars, as well as the bearing bars, are interconnected to form a rigid support. Furthermore, having crossbars which form a level grating surface with the bearing bars eliminates some of the risk of objects, such as bike tires, becoming lodged between the bearing bars.
Therefore, the need has existed for a grating construction which is strong, rigid and safe, which is economical to manufacture, and which includes crossbars which are swage locked with the bearing bars of the grating in such a manner as to form a level grating surface with the bearing bars. There is no known grating construction of which I am aware which accomplishes these results other than my invention which is described in detail below.